Thread grinding machine



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THREAD GRINDING MACHINE Filed March 18, 1942 18 Sheets-Sheet l TTO @gy:

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Nov. 27, 1945. G BRINKMANNIY 2,389,590

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Nov. 27, 1945. G. BRINKMANN 2,3 9,590

THREAD GRINDING MACHINE Filed March 18, 1942 18 Sheets-Sheet 7 Nov. 27,1945. s. BRINKMANN THREAD GRINDING MACHINE Filed March 18, 1942 18Sheets-Sheet 8 Nov. 27,1945: G. BRENKMANN 2,389,599

THREAD GRINDING MACH-INE Filed March 18, 1942 Is Sheets-=Sheea 11 NdvQ27, 1-945. G m N 2,389,590

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THREAD GRINDING MACHINE Filed March 18, 1942 18 Sheets-Sheet 15 E! TEA TSLIP M4NIFOLD g. \D mg 5 8% g WM WWW/0706mm CLUTCH Nov. 27, 1945.

G. BRINKMANN THREAD GRIND ING MACHINE Filed March 18, 1942 18Sheets-Sheet l6 am firw'mfhrzmm E MC' F *W mag-7s Patented Nov. 27, 1945,rnnmn GRINDING monmn Guenther Brinkmann,

Detroit, Mich., assignor to Ex-Cell-O Corporation, Detroit, Mich., acorporation of Michigan Application March 18, 1942, Serial No. 435,224

14 Claims.

The present invention relates to improvements'in thread grindingmachines, and has reference'particularly to machines adapted for thegrinding of internal threads.

One of the objects of the present invention is to provide a novel threadgrinding machine having a longitudinall reciprocable work head, atransversely reciprocable grinding wheel head movable selectivel in onedirection into operative position or in the other direction into idleposition, a dressing mechanism for dressing the grinding wheel in theidle position, and means for imparting a dresser feed to said wheel headand simultaneously adjusting the efiective operative position of thewheel to compensate for the dresser feed.

Another object is to provide a, new and improved internal threadgrinding machine of the foregoing character having an automatic cycle inwhich the grinding wheel will be dressed selectively either after apredetermined number of grinding passes, or after the completion of asingle workpiece, or after the completion of a predetermined number ofworkpieces.

A further object is to provide a. novel thread grinding machine of theforegoing character having cross feed mechanism for imparting anincremental cross feed to the grinding wheel at the end of each grindingpass, and including means selectively available for automaticallyretracting the grinding wheel from the work during the passes in onedirection or the other of the work head reciprocation.

Other objects and advantages will become apparent as the descriptionproceeds.

Referring to the drawings,

Figure 1 is a, front perspective view of a machine embodying thefeatures of the invention.

Fig. 2 is a rear perspective view.

Fig. 3 is a left-end elevational view, partially in section along line3-3 of Fig. 1, and illustrating the work head.

Fig. 4 is a detail sectional view taken along line 4-4 of Fig. 3, andillustrating the speed-change mechanism in the drive for rotating andtranslating the work.

Fig. 5 is a longitudinal vertical sectional view of the work head, takensubstantially along line 5-5 of Fig. 3. V I

Fig. 6 is a transverse vertical sectional view of the work head, takensubstantially along line 6-6 of Fig. 5.

. Fig. 7 is a fragmentary detail view taken along line 1-1 of Fig. 6,and illustrating a gear-change mechanism in the rotary work spindledrive.

Fig. 8 is a fragmentary transverse vertical sectional view takensubstantially along line 8-8 of Fig. 5, and illustrating means 101'eifecting lead pick-up and backlash compensation.

' Fig. 9 is a fragmentary front elevational view illustrating cyclecontrol does and switches operable by the work head.

Fig. 10 is a fragmentary vertical sectional view taken substantiallyalong line ill-l0 01 Fig. 1 through the grinding wheel slide.

Fig. 10;: is a detail sectional view of a switch operating mechanismcontrolled by the wheel slide.

Fig. 11 is a fragmentary vertical sectional view taken along line I l-Il of Fig. 10, and illustrating the actuating means for the cross-feedmechanism.

Fig. 12 is a fragmentary vertical sectional view taken along line I2-l2of Fig. 13, and illustrating a pawl and ratchet drive in the cross-feedmechanism.

Fig. 13 is a vertical sectional view taken substantially along linevl3-l3 of Fig. 12, and illustrating the cross-feed mechanism for thegrinding wheel slide. v

Fig. 14 is a vertical sectional view taken along line H-ll of Fig. 10,and illustrating a dressing feed mechanism for the wheel slide.

Fig. 15 is a fragmentary plan view taken in the direction of the arrowsl5-l5 of Fig. 14, and illustrating a gearing in the dressing feedmechanism.

Fig. 16 is a vertical sectional view taken along line IG-IB of Fig. 13,and illustrating the actuator 01' a wheel retract mechanism associatedwith Q the cross-feed mechanism.

Fig. 17 is a detail sectional view of the crossfeed mechanism takenalong line ll-ll of Fig. 13.

Fig. 18 is a perspective view of certain elements of the retractmechanism shown in exploded relationship.

Fig. 19 is a fragmentary perspective view of the machine, andparticularly illustrating the wheel dressing mechanism and the dressingfeed mechanism.

Fig. 20 is a general diagrammatic representation of the various drivesin the machine.

Fig. 21 is a plan development of index graduations associated with thework spindle.

Fig. 22 is a sectional view taken along line 22-22 of Fig. 14, afidillustrating the actuating means for the dressing feed mechanism.

Figs. 23, 24 and 25 are schematic diagrams While the invention issusceptible of various modifications and alternative constructions, I

have shown in the drawings and will herein describe in detail thepreferred embodiment, but

it is to be understood that I do not thereby in-' tend to limit theinvention to the specific form disclosed, but intend-to cover allmodifications and alternative constructions falling within the spiritand scope of the invention as expressed in the appended claims.

Referring more particularly to the drawings, the machine constitutingthe exemplary embodisionl 'attherearofthegrindingwheelGisa suitabledressing mechanism II for truing the grinding wheel G when the tool headI is shifted into offset idle position. A dresser feed mech-, anism I2is automatically operable to adjust the idle position of the tool head Iincrementally to ward the dressing tools for each dressing operation,and simultaneously to adjust the operative position of the tool headrelatively to the workpiece W independently of the cross feed mechanismI to compensate for the reduction in diameter of the grinding wheel G inthe dressing operation.

The operation of the machine is controlled by an electrical system inwhich the movements of th main units are interlocked and timed, and

which is selectively adjustable to obtain any one of a substantialnumber of automatic machine merit of the invention is of the typeadapted for grinding internal screw threads, and comprises an elongatedhorizontally disposed base i formed on the top with a longitudinalset ofways 2 for supporting a work head I, and having a rearward extension Iformed with a set of transverse ways I for supporting a tool head I. Arotary ltool spindle 1 is mounted in the tool head I and supports asuitable grinding wheel G. A work spindle 8 is mountedin the work headI, and is adapted to rotate and translate a workpiece W axially throughcutting engagement with the grinding wheel G in timed relation to therotation as determined by the lead of the thread or threads to be groundThe tool head I is shiftable transversely of the work spindle I tolocate the grinding wheel G either in operative position at the forwardlimit of travel or in idle or dressing position at the rearward limit oftravel. when the grinding wheel G is located in the operative position,it is substantially alined with the work spindle I to enter and take agrinding pass or series of passes through the workpiece W. Relativeworking translation between the grinding wheel G and the workpiece W isobtained by reciprocating the work spindle I through a selected programof movements, such for example as a rapid approach to grinding position,a slow iorward feed through the working range, and a rapid return toidle position. v

The spindle I may be rotated in either direction relative to thetranslation in accordance-with the hand of the thread to be ground. Ateach reversal of translation, the rotation of thespindie I is reversed,and the spindle is'shifted axially to'compensate for backlash in thedrive:. The work spindle I also is shiftable axially for lead pickup,and is adapted to be indexed when grinding multiple threads to locatethe threads successively in correct cutting relation to the grind.

ing wheel G.

A cross feed mechanism I is provided for automatically adjusting theoperative position of the wheel G step-by-step in timed relation to thesuccessive working passes of the spindle I until the workpiece W hasbeen ground to ilnal size. A retract mechanism III is automaticallyoperable to separate the grinding wheel G laterally from the workpiece Wduring all rapid traverse movements without aifecting the setting oi thecross feed mechanism.

Mounted in a fixed position on the base extenwithinthe capacity of thecounting mechanism.

The work head The work head I comprises a longitudinal subbase or slideII which is mounted on the ways 2 or the machine 'base I for manualadjustment longitudinally of the work spindle I, and which. during thenormal machine operation, is clamped in position of adjustment.

To provide means for eifecting the manual ad- ,iustment, the outer endof the base slide 20 is formed between the ways 2 with a longitudinalbore 2| having a counterbore 22. A stationary nut II is fitted inthe'counterbore II, and has an outer .end flange II bolted to the slideII. An adjusting screw, II extends through threaded engagement with thenut II into the bore 2|. The outer end of the screw II is rotatablyanchored against endwise movement in an end wall II on the machine baseI, and has a squared end I1 for engagement by a suitable hand tool (notshown).

The base .slide- II is adapted to be secured adjacent its ends to thebase i by two similar manually operable clamping devices. Each clampingdevice comprises transverse clamping bar II slidably engaging atopposite endsin two longitudinal grooves II formed in the inner sides ofthe ways 2. A clamping plunger II extends upwardly through an opening inan intermediate portion of the clamping bar II and has a head IIengaging the underside thereof. The upper end or the plunger II extendsslldably into a vertical bore II in the base slide II, and is formed inone side with a conical recess II. A clamp screw II isadjustablythreaded through the base slide II into the bore I2, and has aconical pin II on the inner end adapted for wedge engagement with theupper side of the recess II. The screw II is provided with a squared endII adapted to be engaged by a suitable hand tool (not shown). It will beseen that when the screw II is turned inwardly, the plunger II will beforced upwardly to clamp the bar II securely against the upper sides ofthe grooves II 'in any position of adjust

